1. Field of the Invention
The present invention relates to therapeutic medical devices for improving venous blood flow in a patient. More particularly, the invention relates to a connector for providing a continuous fluid passageway between a source of pressurized fluid and a compression sleeve.
2. Description of the Prior Art
Therapeutic medical devices are known for reducing the occurrence of deep vein thrombosis (DVT) and pulmonary embolism in recumbent users. Such devices operate by applying pressure to the limb of a patient. The applied pressure prevents pooling of the blood in the limb by forcing the venous blood to return to the heart. Typically, the devices include a controller for regulating a source of pressurized fluid, such as air, and a compression sleeve which communicates with the controller through a fluid connector. The compression sleeve is placed around the limb of the patient and the controller regulates inflation and venting of the compression sleeve. The connector provides a continuous fluid passageway between the source of pressurized fluid and the compression sleeve.
Prior art connectors for compression systems are subject to leaking pressurized fluid at the joints between the connector and the controller, and at the joints between the connector and the compression sleeve. For many reasons, it is desirable for the connector to be quickly and easily removable, particularly at the interface between the controller and the connector. Rapid and repeated connections, however, increase the likelihood of leakage of the pressurized fluid which reduces the efficiency of the compression system and creates contamination problems. Leakage occurs primarily when the connections are improperly made, when the connecting portions become worn, or when stresses are inadvertently applied to the ends of the connector.
A connector for use with a therapeutic compression system is described in U.S. Pat. No. 4,253,449 to Arkans et al. The connector includes a first connection member which is rigidly secured on each side to retaining flanges on a controller. The first connection member includes a plurality of cylindrical ports with passageways therethrough for communicating with a second connection member. A plurality of tubular sections are retained by the second connection member such that when the second connection member is received between the retaining flanges of the controller, the tubular sections are in abutting relation with the cylindrical ports on the first connection member. O-rings are provided on the outer diameter of the cylindrical ports for forming a seal with the second connection member to prevent leakage of the pressurized fluid from the controller. The connection between the first connection member and the second connection member is accomplished by positioning the second connection member between the retaining flanges and over the O-rings on the outer diameter of the cylindrical ports of the first connection member. Thus, a fluid-tight seal is made only if the dimensional tolerances of the first connection member, the retaining flanges, the second connection member and the tubular sections are tightly controlled. Because the O-rings which seal the interface between the first connection member and the second connection member are on the outer diameter of the ports, leakage can occur at the abutting interface between the ports and the tubular sections if the tubular sections are loosely retained in the second connection member, or are not retained in parallel relationship with the ports.
The connector includes a conduit having a plurality of passageways therethrough which abut the tubular sections retained by the second connection member. At their downstream ends, the plurality of passageways are attached to a corresponding plurality of tubular sections retained in a third connection member. The third connection member acts as a manifold to distribute the pressurized fluid in the conduit into two separate conduits for delivering the pressurized fluid to compression sleeves on each of the patient's legs. Because the manifold separates the connector conduit into two additional conduits, the number of joints through which the pressurized fluid must pass is thereby multiplied. Thus, the potential for leakage of the pressurized fluid or contamination of the fluid stream is greatly increased.
Another problem encountered with prior art fluid connectors for compression systems is that the connector is not easily or rapidly removable from the controller. The connector described in the Arkans et al. patent is not easily grasped and removed. Only a portion of the second connection member extends beyond the retaining flanges on the controller. Thus, it is difficult to firmly grasp the second connection member for aligning, connecting and disconnecting the first connection member and the second connection member. As a result, substantial mechanical stresses and strains are transferred to the tubular sections retained by the second connection member. With repeated use, the joints between the tubular sections and the ports are weakened and the likelihood of leakage of the pressurized fluid or contamination of the fluid stream is greatly increased.